the main problem with no wild battles is that wild pokemon then become worthless unless you happen to see a shiny or something, if shinies are even in this game.
you catch a pokemon once and then running into that pokemon again isnt fun or even meaningful its just annoying. atleast before when you saw a million zubats you got exp. it also severly cuts down on the time it takes to beat the game if you can just walk around all the pokemon.